“In the fall, many of the ornamental grasses that looked so nice over the summer are beginning to look a little shabby and worn. Can they be cut back now, or should I wait until colder weather?” -Bill
Traditionally, ornamental grasses are cut back in the late winter or early spring, for two main reasons:
- The dormant foliage provides some winter interest in an otherwise bare garden.
- The foliage provides some insulating protection from cold and soaking rains.
The cold protection is important if you are planting grasses only marginally hardy to your zone. Leaving the foliage over the winter can insulate the plant and increase its chances of surviving the winter. The foliage also shields water from the crown, helping to prevent rot.
If you live in a warmer climate, or if you are planting grasses that are winter hardy in your zone, when to cut them back is really a matter of preference. Some gardeners like the “neat and tidy” look over the winter, while others like the swaying and crackling grasses in the landscape. In warmer areas, cutting grasses back in the fall can actually stimulate next year’s growth, giving you an early start next season.